The present disclosure relates to harvesting articulated (jointed) combines and more particularly to improved airflow in the forward tractor or crop processing power unit (PPU) having dual engines with all grain stored in a rear grain cart.
Most modern combines that utilize axially mounted threshing rotors have a single engine that is mounted transverse to the rotor (and direction of travel). Those combines typically use a bevel gear set to “turn” the engine's power to rotate the primary power consuming components—the rotor(s), header, and chopper(s). This configuration comes with several problems.
One problem is that axial combines with transverse mounted engines utilize an expensive, heavy, space, and energy consuming bevel gear set to “turn” the power needed for the rotor. Modern combines that package the engine parallel to the threshing cylinder, when the cylinder is mounted axially to the direction of travel, were developed to eliminate the bevel gear set. However, when a single engine is used and not mounted on the centerline of the machine, it generally causes a left-right weight imbalance, which is a second problem. This phenomenon is exasperated by the demand for higher horsepower combines that use larger (and heavier) diesel engines. Adding to the weight imbalance is the need for pump drive gearboxes in addition to the power takeoff. These gearboxes are typically mounted to the engine flywheel housing. They are heavy and expensive and typically contain one or more clutches that require hydraulic pressure and flow for actuation and lubrication.
A third problem is that crop residue that exits the combine is flammable and catches fire when it comes to rest on engine exhaust components. Combine combustion air pre-cleaning traditionally uses a collection of multiple “spin tubes” that separate dust from the combustion air prior to air filtration. The separated dust is generally evacuated from the pre-cleaner housing via a mechanically driven suction fan or exhaust venturi. Pre-cleaning is used to extend combustion air filter life. Crop debris, like soybean fuzz, is difficult to separate in the pre-cleaner, as that debris is relatively long and light compared to dust from dirt. Larger spin tubes have been designed with limited success. A fourth problem, then, is that combine filter life generally is poor due to inadequate pre-filter air cleaning.
Accordingly, an air handling, flow, and filtering system that addresses these and other issues is needed.